Stir together the sugar, cola, mustard, and pineapple juice in a small, microwave safe bowl. Microwave for 2 minutes. (*see notes about doubling ham glaze for later use)
Place ham in the pot of the slow cooker. Pour the the glaze over the ham. If your ham is spiral sliced, be sure the glaze gets between the slices.
Cook on low for 4-6 hours or high for 3-4 hours until ham reaches an internal temperature of 145ºF.
Remove ham from the slow cooker and tent with foil. Drizzle ham with leftover cola mixture. Let rest 10-15 minutes before serving.
Notes
*For plenty of extra glaze to use on top of the cooked ham, double the Coke and pineapple glaze mixture called for above. Use half of the glaze for cooking the ham, and save the other half for drizzling over the cooked ham once it's done.Refrigerate ham for up to 5 days or freeze for up to 4 months.